scsi: qla2xxx: Simplification of register address used in qla_tmpl.c

Reduce stack space on each fwdt routine by eliminating local variable reg.

Signed-off-by: Joe Carnuccio <joe.carnuccio@cavium.com>
Signed-off-by: Himanshu Madhani <hmadhani@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>